1. Field of the Invention
This invention relates to control of the steam flow to a steam and water mixing hose station where control of the steam flow and the temperature of the mixed steam and water is accomplished by sensing the temperature of the mixture and regulating the steam flow to maintain the temperature of the mixture at a preset value.
2. Description of the Prior Art
Hose stations are known in the art. Such stations mix hot water or steam with cold water, and the mixture is used to wash down animal carcasses, machinery and other items. Such stations typically include a supply of steam under pressure and a supply of cold water under pressure, which are mixed in a mixing chamber. A hose is connected to the outlet of the mixing chamber from which the mixture is available as required. The flow of steam and water to the mixing chamber is usually controlled by conventional, manually adjustable, shut-off valves on the supply lines, which are satisfactory so long as there is no pressure drop in the flow of steam or water. The temperature of the mixture is determined by various safety and operational considerations, and for animal carcasses must be maintained within a narrow range.
The steam supplied can be at a pressure of up to 150# and the cold water up to 100#. The steam temperature can be up to 366.degree. F. The high temperatures and pressures may cause a hazardous condition, and injury to the operator and other persons result, should the water pressure drop suddenly resulting in the temperature of the mixture rising to an unacceptable level. A drop in steam pressure can cause the temperature of the mixed cold water and steam to drop below the required operational temperatures.
Precise automatic control of the steam/water output temperature is therefore necessary at all times for safety and operational reasons.